I'm having this same problem. It's really sad that Verizon does not seem interested in helping us address this issue. One of the reasons I switched to Verizon was because I thought they would have better customer service than most phone providers. I'm afraid I was wrong and am just about ready to switch back to something cheaper.
I'm sorry for the concerns you have experiencing on the Cosmos 2! To remove the application, you want to navigate to Browse and Download, then just highlight Backup Assistant (without pressing OK to open), then you'll see Options appear in the lower right corner. Select Options, then 'Cancel Subscription' to confirm and remove. After removal, you can then redownload it and start as a new user with your new mobile telephone number. I hope that helps!
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